Spoilers are precisely defined here. Rules vary by the story's medium. Info from television stories can't be added here until after the top or bottom of the hour, British time, closest to the end credits roll on BBC One. Therefore, fans in the Americas who are sensitive to spoilers should avoid Tardis on Sundays until they've seen the episode.
When the Fifth Doctor evaded the Time Lord's calls for help regarding Abby and Zara, Lowri, who was still president, used the Vortex Manipulator to interrupt the Doctor's travels and meet Leela. (AUDIO: The Garden of Storms)
The Presidents are categorised by in-universe chronological order. Loose chronological order applies for the lists, but when in doubt (as with the temporal uncertainty of the Time Wars), list them in the order in which they were first depicted as Presidents in the real world.